My company phone is a Redmi Note 7. Aside from the quirkiness of MIUI, it works just as well

You can't compare the camera quality just by quoting the model of the camera sensor. The sensor is just one part of the camera module. One drawback of the imx586 sensor is its tiny pixel size which means less details in low light especially on cheap/midrange phones without OIS. Even with pixel binning you can see that there are less details in low light in the Mi A3 camera review vs the Realme 3 pro/A2/Pocophone. This was something I saw when I compared the new RN7 with the Mi A2  review camera samples.
That doesn't make the RN7 or Mi A3 bad, the cameras are quite good actually but not "way better" than the Realme 3 pro as you have said. The R3pro camera quality is on par with its Xiaomi competitors.

The Realme 3 pro supports camera2api in stock rom so no need for root (but allows rooting) and also has working gcam ports for better pictures.

I have been using Mi A3 for a week, coming from Honor 10's 1080p LCD display I don't really notice any pixellation. Maybe my eyes are not that sensitive.

I read GSMArena review mentioning about jagged text in the display and went to check out the phone in a Xiaomi outlet, didn't notice it and straightaway bought it.

The rest is like Ehtan Hunt mentioned in the previous page. Pretty good camera, amazing battery life.

Built quality is also on par with Honor 10. Vast improvement compared to my Redmi note 4 from couple years ago.

Gaming performance also good. It only feels 1 degree celcius warmer after playing Mobile Legends for half an hour, with the stock provided transparent casing on.